This invention is related to insert type casing cementing equipment for use in the cementing of the casing in oil and gas wells and the like.
When cementing casing into a well bore in oil and gas wells and the like, commonly the casing equipment used in the well cementing operations has been attached to the casing by the use of either threads or welding of both. However, these types of attachments are used when the casing equipment is attached at the end of the casing string or at a connection between two strings of casing.
Also, problems arise when trying to provide casing equipment with compatible threads to that of the casing string since there are many different types of threads and thread manufacturers. Similarly, problems arise when trying to employ welding to secure the casing equipment to the casing string. For instance, the quality of the weld cannot be predicted because, in many instances, the metallurgical composition of the casing is unknown. Additionally, due to the localized heating of the casing during welding operations of the casing equipment to the casing stress concentrations will likely be present.
Typical prior art insert type casing equipment is shown in U.S. Pat. Nos. 3,120,269, 4,901,794, and 4,934,459.
The insert type casing cementing equipment shown in the '269 Evans et al. patent utilizes an elastomeric compression type sealing member.
The insert type casing shown in the '794 and '459 Baugh et al patents utilize a deformable metal seal having a grit like gripping surface as a compression type sealing member and a back-up annular elastomeric sealing member.
The prior art insert type equipment is set in the casing by causing relative motion between portions of the equipment to cause the compression type sealing members to engage the interior of the casing.